Fungicidal composition and method of combating fungi

ABSTRACT

Spiroheterocyclic compounds having fungicidal activity are disclosed having the formula: ##STR1## in which X is O or CH 2  ; R 1  is hydrogen or optionally substituted alkyl, cycloalkyl, haloalkyl, alkenyl, alkynyl, aryl or aralkyl; R 2  is optionally substituted alkyl, cycloalkyl, cycloalkylalkyl, alkoxy, alkoxyalkyl, aryl or aryloxy, or together with the ring to which they are attached represents a polycyclic hydrocarbyl group; A and B both represent nitrogen, or A represnts the gorup CR 5  and B represents nitrogen or CR 6  ; 1 is an integer from 1 to 3; m is zero or an integer from 1 to 6; and n represents zero or an integer from 1 to 3.

The present invention relates to certain new spiroheterocyclic compoundshaving fungicidal properties, processes for the preparation of thesecompounds, fungicidal compositions containing the compounds and the useof the compounds as fungicides for the control of phytopathogenic fungi.

In EP 281842, EP 349247 and EP 413223 fungicidal spiroheterocycliccompounds have been described. These known compounds contain asubstituted cyclohexyl ring in spiro conjunction with a substitutedheterocyclic five or six membered ring. The substituents of thecyclohexyl ring are usually (substituted) (branched) alkyl or phenylgroups. The substituents of the heterocyclic ring are usually(substituted) (cyclo)alkyl- or dialkyl-amino-methyl ordialkyl-amino-polymethyl groups, including alkylene-amino-methyl oralkylene-amino-polymethyl groups. Other fungicidal spiroheterocycliccompounds have been described in EP 278352 and WO 92/16518.

It has now been found that certain new spiroheterocyclic compounds showexcellent fungicidal activity against certain phytopathogenic fungi, forinstance against Plasmopora viticola, Botrytis cinerea, Erysiphegraminis, Pseudocercosporella herpotrichoides, Rhizoctonia solani andVenturia inaequalis.

The present invention therefore relates to compounds of the generalformula I ##STR2## in which X represents O or CH₂,

R¹ represents a hydrogen atom or an optionally substituted alkyl,cycloalkyl, haloalkyl, alkenyl, alkynyl, aryl or aralkyl group,

R² or each R² independently represents an optionally substituted alkyl,cycloalkyl, cycloalkylalkyl, alkoxy, alkoxyalkyl, aryl or aryloxy group,or R² or each R², together with the ring to which they are attached,represents a polycyclic hydrocarbyl group,

A and B both represent a nitrogen atom, or A represents a group CR⁵ andB represents a nitrogen atom or a group CR⁶,

R³, R⁴, R⁵ and R⁶ each independently represent a hydrogen or halogenatom, a hydroxy or cyano group or an optionally substituted alkyl,alkenyl, alkynyl, haloalkyl, alkoxyalkyl, aralkyl, aryl, alkylamino,alkenylamino, alkylthio, alkoxy, alkenoxy or alkynoxy group,

l represents an integer from 1 to 3,

m represents zero or an integer from 1 to 6, and

n represents zero or an integer from 1 to 3.

The invention especially relates to compounds of the general formula Iin which any alkyl, alkenyl, alkynyl part of any of the substituents R¹to R⁶ contains up to 12 carbon atoms, preferably up to 10 carbon atoms,more preferably up to 8 carbon atoms, any cycloalkyl part of any of thesubstituents R¹ to R⁶ contains from 3 to 10 carbon atoms, preferablyfrom 3 to 8 carbon atoms, more preferably from 3 to 6 carbon atoms, anyalkylene chain contains from 3 to 6 chain members, and any aryl part ofany of the substituents R¹ to R⁶ contains 6, 10 or 14 carbon atoms,preferably 6 or 10 carbon atoms, and in which each optionallysubstituted group independently is substituted by one or more halogenatoms or nitro, cyano, alkyl, preferably C₁₋₆ alkyl, cycloalkyl,preferably C₃₋₆ cycloalkyl, haloalkyl, preferably C₁₋₆ haloalkyl,halocycloalkyl, preferably C₃₋₆ halocycloalkyl, alkoxy, preferably C₁₋₆alkoxy, haloalkoxy, preferably C₁₋₆ haloalkoxy, optionally substitutedamino, acyl, alkoxycarbonyl, preferably C₁₋₆ alkoxycarbonyl, carboxyl,phenyl or halo- or dihalo-phenyl groups. Optionally substituted aminogroups include amino groups substituted by one or two groups selectedfrom alkyl, aryl, cycloalkyl, cycloalkylalkyl and aralkyl groups, inparticular alkylamino, dialkylamino, arylamino, haloarylamino andbenzylamino. Any acyl group includes formyl, optionally substitutedalkyl carbonyl and optionally substituted aryl carbonyl groups. Anyalkyl, alkenyl or alkynyl group may be linear or branched. Preferredalkyl substituents are at least methyl, ethyl, propyl and butyl. Ahalogen atom suitably denotes a fluorine, chlorine or bromine atom.

The invention especially relates to compounds of the general formula I,in which X represents O.

The invention further especially relates to compounds of the generalformula I in which R¹ represents a hydrogen atom, a C₁₋₆ alkyl, C₃₋₆cycloalkyl, C₂₋₆ alkenyl, C₂₋₆ alkynyl, phenyl or benzyl group, eachgroup optionally substituted by one or more halogen atoms, especiallychlorine and/or fluorine atoms, or C₁₋₄ alkyl, C₁₋₄ haloalkyl, C₁₋₄alkoxy, C₁₋₄ alkylamino, C₁₋₄ dialkylamino or phenylamino groups. R¹preferably represents a hydrogen atom or a methyl or ethyl groupoptionally substituted by up to three chlorine or fluorine atoms, anethenyl, propenyl or propynyl group or a phenyl or benzyl group.

The invention also especially relates to compounds of the generalformula I in which R² or each R² represents a C₁₋₁₀ alkyl, C₃₋₆cycloalkyl, C₃₋₈ cycloalkyl-C₁₋₆ alkyl, C₁₋₆ alkoxy, C₁₋₁₀ alkoxy-C₁₋₆alkyl or phenyl group, or R² or each R² together with the ring to whichthey are attached, represents a C₇₋₂₀ polycyclic group, preferably aC₈₋₁₂ bicyclic, C₉₋₁₄ tricyclic or C₉₋₁₆ quadricyclic hydrocarbyl group,preferably a saturated hydrocarbyl group, each of the above groupsoptionally substituted by one or more halogen atoms, especially chlorineand/or fluorine atoms, or C₁₋₄ alkyl, C₁₋₄ haloalkyl or C₁₋₄ alkoxygroups. R² preferably represents a C₁₋₈ alkyl group, especially abranched alkyl group. Especially suitable are secondary and tertiaryalkyl groups as secondary butyl, tertiary butyl and tertiary amylgroups. More preferably R² represents a t-butyl or t-amyl group. Theinvention also especially relates to compounds of the general formula Iin which m represents an integer from 1 to 4, preferably 1 or 2, morepreferably 1. The group or groups R² are preferably attached to thepositions 3, 4 and/or 5 of the cycloalkyl ring, especially a cyclohexylring, more preferably to the 4-position.

The invention further especially relates to compounds of the generalformula I in which A and B both represent a nitrogen atom or Arepresents a group CR⁵ and B represents a nitrogen atom. Preferably Arepresents a group CR⁵ and B represents a nitrogen atom.

The invention further especially relates to compounds of the generalformula I in which R³, R⁴, R⁵ and R⁶ each independently represent ahydrogen or halogen atom, a hydroxy group or an optionally substitutedC₁₋₈ alkyl, C₁₋₆ alkenyl, C₁₋₆ haloalkyl, benzyl, phenyl or C₁₋₆ alkoxygroup, each group optionally substituted by one or more halogen atoms,especially chlorine and/or fluorine atoms, or C₁₋₄ alkyl, C₁₋₄haloalkyl, C₁₋₄ alkoxy, C₁₋₄ alkylamino, C₁₋₄ dialkylamino orphenylamino groups. R³ and R⁴ each independently preferably represent ahydrogen or halogen atom, especially a chlorine or fluorine atom, ahydroxy group or a methyl, ethyl, propyl, butyl, pentyl, hexyl, phenyl,methoxy or ethoxy group, each group optionally substituted by up to fivechlorine or fluorine atoms, especially three chlorine or fluorine atoms.R⁵ and R⁶ each independently preferably represent a hydrogen or halogenatom, especially a chlorine or fluorine atom, or a methyl, ethyl,propyl, methoxy or ethoxy group, each group optionally substituted by upto three chlorine or fluorine atoms.

The invention especially relates to compounds of the general formula Iin which 1 represents 1 and n represents 1.

A particular preferred sub-group of compounds of the general formula Iis that in which R¹ represents a hydrogen atom. Another preferredsub-group of compounds of the general formula I is that in which R² oreach R² independently represents a methyl, propyl, especially i-propyl,butyl, especially t-butyl, pentyl, especially t-amyl, cyclohexyl orphenyl group, or in the case of a polycyclic structure, two groups Rrepresent a tetra- or penta-methylene group. Further preferredsub-groups of the general formula I are those in which R³ and R⁴ eachindependently represent a hydrogen or chlorine atom or a methyl, butyl,especially i-butyl, or methoxy group, and R⁵ and R⁶ each independentlyrepresent a hydrogen atom or a trifluoromethyl group.

The present invention further provides a process for the preparation ofcompounds of the general formula I as defined hereinbefore in which Xrepresents O, which process comprises reacting a compound of the generalformula II ##STR3## in which R², n and m are as defined hereinbefore,with a compound of the general formula III ##STR4## in which R¹, R³, R⁴,A, B and 1 are as defined hereinbefore, as well as a process for thepreparation of compounds of the general formula I as definedhereinbefore and in which X represents 0 or CH₂, which process comprisesreaction of a compound of the general formula IV ##STR5## in which R¹,R², l, m and n are as defined hereinbefore, with a compound of thegeneral formula V ##STR6## in which R³, R⁴, A and B are as definedhereinbefore and Z represents a leaving group, or, optionally, in thecase A represents a group CR⁵ and B represents N, by reaction of acompound of the general formula IV with a compound of the generalformula VI ##STR7## in which P represents a leaving group, followed byreaction with a compound of the general formula VII ##STR8## in whichR³, R⁴ and R⁵ are as defined hereinbefore, while in the case that R¹represents a hydrogen atom, this hydrogen atom may be exchanged byanother substituent within the definition of R¹ by reaction with asuitable alkylating agent.

It will be appreciated that between the above indicated reaction stepsadditional chemical modification can be made to the compounds obtained,e.g. introduction or amendment of certain substituents in the cycloalkylor heteroaromatic ring.

The starting compounds with the general formula II are known in theliterature, and many of them are commercially available.

Compounds of the general formula III are new compounds. These compoundsform part of the present invention. These compounds may be prepared byoxidation of an alkene of the general formula VIII ##STR9## in which R¹,R³, R⁴, A, B and 1 are as defined hereinbefore with a suitable oxidant,for instance with potassium permanganate or, especially, osmiumtetroxide, especially a catalytic amount thereof together with aregeneration reagent. The alkenes of the general formula VIII may beprepared by reaction of a (substituted) alkenylamine with a compound ofthe general formula V as defined above, or by reaction of a(substituted) alkenylamine and a compound of the general formula VI asdefined above, followed by reaction with a compound of the generalformula VII as defined above. Compounds of the general formulas VI andVII are known in the literature, or can be prepared in analogous ways.Alternatively, compounds of the general formula III can be prepared byreaction of a compound of the general formula V with a compound of thegeneral formula XI ##STR10## in which R¹ and 1 are as definedhereinbefore.

Compounds of the general formula IV can be prepared by reaction of acompound of the general formula X ##STR11## in which R², X, l, m and nare as defined hereinbefore and Q represents a leaving group, with acompound of the formula R¹ -NH₂, in which R¹ represents a hydrogen atomor an optionally substituted alkyl, cycloalkyl, haloalkyl, alkenyl,alkynyl, aryl or aralkyl group. Compounds of the general formula X areknown from the literature, see for example EP 281842, EP 413223 and EP278352.

A leaving group is any group that, under the reaction conditionsappropriate for the reaction involved, will cleave from the startingmaterial, thus enabling substitution at that specific site. The leavinggroup Z may suitably be a halogen atom, for example a bromine atom or,especially, a chlorine atom, an alkoxy group, suitably C₁₋₄ alkoxy,especially methoxy, an alkyl- or arylsulphonium group, especially a C₁₋₆alkyl-, phenyl- or tolylsulphonium group, or an alkyl- or aryl-sulphonicacid group, especially a C₁₋₆ alkyl-, phenyl- or tolyl-sulphonic acidgroup. The leaving group P is suitably an alkoxy or alkylthio group,suitably a C₁₋₄ alkoxy or C₁₋₄ alkylthio group, especially a methoxy ormethylthio group. The leaving group Q may suitably be a halogen atom,for example a bromine atom or, especially, a chlorine atom, an alkyl- oraryl-sulphonium group, especially a C₁₋₆ alkyl-, phenyl- ortolyl-sulphonium group, or an alkyl- or aryl-sulphonic acid group,especially a C₁₋₆ alkyl-, phenyl- or tolyl-sulphonic acid group.

The process of the present invention in which the heterocyclicspirocompound is formed is suitably carried out in the presence of anorganic solvent, for example an alkane, an aromatic solvent, achlorinated hydrocarbon or an ether. Especially suitable are thoseorganic solvents which form an azeotrope with water, such as benzene,toluene, chloroform etc.

The process is suitably carried out at a temperature in the range of 0°to 150° C., especially between 40° and 120 ° C., preferably at thereflux temperature of the solvent, and suitably in the presence of aacid.

Suitably the reaction is carried out using substantially equimolaramounts of the reactants. However, it can be expedient to use onereactant in excess.

The process of the present invention in which a compound of the generalformula IV is reacted with a compound of the general formula V or VI maybe carried out in the presence or absence of an organic solvent, forexample an alcohol or a formamide. Especially suitable are polar organicsolvents as dimethylsulfoxide and hexamethylphosphortriamide.

The reaction is suitably carried out at a temperature in the range of50° to 250° C., especially between 90° and 210 ° C.

The reaction of the present invention in which the intermediate formedafter the reaction of a compound of the general formula IV with acompound of the general formula VI is reacted with a compound of thegeneral formula VII is preferably carried out in the presence of anorganic solvent, for example an alkane, an aromatic solvent, achlorinated hydrocarbon or an ether. Especially suitable are thoseorganic solvents which form an azeotrope with water, such as benzene,toluene, chloroform etc.

The process is suitably carried out at a temperature in the range of 0°to 150° C., especially between 40° and 120 ° C., preferably at thereflux temperature of the solvent, and suitably in the presence of aacid.

The invention also provides fungicidal compositions comprising at leastone of the compounds according to general formula I or an acid additionsalt thereof, as well as methods of combating fungi at a locuscomprising treatment of the locus with a compound of formula I or anacid addition salt thereof as defined hereinbefore, or with acomposition as defined in this specification. The locus to be treatedespecially comprises plants subject to or subjected to fungal attack,seeds of such plants or the medium in which the plants are growing orare to be grown.

The fungicidal composition comprises a carrier and, as activeingredient, a compound of the general formula I or an acid addition saltthereof.

A method of making such a composition is also provided, which comprisesbringing a compound of the general formula I as defined above or an acidaddition salt thereof into association with at least one carrier. Such acomposition may contain a single compound or a mixture of severalcompounds of the present invention. It is also envisaged that differentisomers or mixtures of isomers may have different levels or spectra ofactivity and thus compositions may comprise individual isomers ormixtures of isomers.

The invention further relates to the use as a fungicide of a compound offormula I as defined hereinbefore or a composition as definedhereinbefore.

A composition according to the invention preferably contains from 0.5 to95% by weight of active ingredient.

A carrier in a composition according to the invention is any materialwith which the active ingredient is formulated to facilitate applicationto the locus to be treated, which may for example be a plant, seed orsoil, or to facilitate storage, transport or handling. A carrier may bea solid or a liquid, including a material which is normally gaseous butwhich has been compressed to form a liquid, and any of the carriersnormally used in formulating fungicidal compositions may be used.

Suitable solid carriers include natural and synthetic clays andsilicates, for example natural silicas such as diatomaceous earths;magnesium silicates, for example talcs; magnesium aluminium silicates,for example attapulgites and vermiculites; aluminium silicates, forexample kaolinites, montmorillonites and micas; calcium carbonate;calcium sulphate; ammonium sulphate; synthetic hydrated silicon oxidesand synthetic calcium or aluminium silicates; elements, for examplecarbon and sulphur; natural and synthetic resins, for example coumaroneresins, polyvinyl chloride, and styrene polymers and copolymers; solidpolychlorophenols; bitumen; waxes, for example beeswax, paraffin wax,and chlorinated mineral waxes; and solid fertilisers, for examplesuperphosphates.

Suitable liquid carriers include water; alcohols, for exampleisopropanol and glycols; ketones, for example acetone, methyl ethylketone, methyl tsobutyl ketone and cyclohexanone; ethers; aromatic oraraliphattc hydrocarbons, for example benzene, toluene and xylene;petroleum fractions, for example, kerosine and light mineral oils;chlorinated hydrocarbons, for example carbon tetrachloride,perchloroethylene and trichloroethane. Mixtures of different liquids areoften suitable.

Fungicidal compositions are often formulated and transported in aconcentrated form which is subsequently diluted by the user beforeapplication. The presence of small amounts of a carrier which is asurface-active agent facilitates this process of dilution. Thuspreferably at least one carrier in a composition according to theinvention is a surface-active agent. For example the composition maycontain at least two carriers, at least one of which is a surface-activeagent.

A surface-active agent may be an emulsifying agent, a dispersing agentor a wetting agent; it may be nonionic or ionic. Examples of suitablesurface-active agents include the sodium or calcium salts of polyacrylicacids and lignin sulphonic acids; the condensation products of fattyacids or aliphatic amines or amides containing at least 12 carbon atomsin the molecule with ethylene oxide and/or propylene oxide; fatty acidesters of glycerol, sorbitol, sucrose or pentaerythritol; condensates ofthese with ethylene oxide and/or propylene oxide; condensation productsof fatty alcohol or alkyl phenols, for example p-octylphenol orp-octylcresol, with ethylene oxide and/or propylene oxide; sulphates orsulphonates of these condensation products; alkali or alkaline earthmetal salts, preferably sodium salts, of sulphuric or sulphonic acidesters containing at least 10 carbon atoms in the molecule, for examplesodium lauryl sulphate, sodium secondary alkyl sulphates, sodium saltsof sulphonated castor oil, and sodium alkylaryl sulphonates such asdodecylbenzene sulphonate; and polymers of ethylene oxide and copolymersof ethylene oxide and propylene oxide.

The compositions of the invention may for example be formulated aswettable powders, dusts, granules, solutions, emulsifiable concentrates,emulsions, suspension concentrates and aerosols. Wettable powdersusually contain 25, 50 or 75% w of active ingredient and usually containin addition to solid inert carrier, 3-10% w of a dispersing agent and,where necessary, 0-10% w of stabiliser(s) and/or other additives such aspenetrants or stickers. Dusts are usually formulated as a dustconcentrate having a similar composition to that of a wettable powderbut without a dispersant, and may be diluted in the field with furthersolid carrier to give a composition usually containing 1/2-10% w ofactive ingredient. Granules are usually prepared to have a size between10 and 100 BS mesh (1.676-0.152 mm), and may be manufactured byagglomeration or impregnation techniques. Generally, granules willcontain 1/2-75% w active ingredient and 0-10% w of additives such asstabilizers, surfactants, slow release modifiers and binding agents. Theso-called "dry flowable powders" consist of relatively small granuleshaving a relatively high concentration of active ingredient.Emulsifiable concentrates usually contain, in addition to a solvent and,when necessary, co-solvent, 1-50% w/v active ingredient, 2-20% w/vemulsifiers and 0-20% w/v of other additives such as stabilisers,penetrants and corrosion inhibitors. Suspension concentrates are usuallycompounded so as to obtain a stable, non-sedimenting flowable productand usually contain 10-75% w active ingredient, 0.5-15% w of dispersingagents, 0.1-10% w of suspending agents such as protective colloids andthixotropic agents, 0-10% w of other additives such as defoamers,corrosion inhibitors, stabilisers, penetrants and stickers, and water oran organic liquid in which the active ingredient is substantiallyinsoluble; certain organic solids or inorganic salts may be presentdissolved in the formulation to assist in preventing sedimentation or asanti-freeze agents for water.

Aqueous dispersions and emulsions, for example compositions obtained bydiluting a wettable powder or a concentrate according to the inventionwith water, also lie within the scope of the invention. The saidemulsions may be of the water-in-oil or of the oil-in-water type, andmay have a thick `mayonnaise` like consistency.

The composition of the invention may also contain other ingredients, forexample other compounds possessing herbicidal, insecticidal orfungicidal properties.

Of particular interest in enhancing the duration of the protectiveactivity of the compounds of this invention is the use of a carrierwhich will provide a slow release of the fungicidal compounds into theenvironment of the plant which is to be protected. Such slow-releaseformulations could, for example, be inserted in the soil adjacent to theroots of a vine plant, or could include an adhesive component enablingthem to be applied directly to the stem of a vine plant.

The present invention still further provides the use as a fungicide of acompound of the general formula I as defined above or a composition asdefined above.

The present invention is of wide applicability in the protection of cropplants against fungal attack. Typical crops which may be protectedinclude cereals, especially wheat and barley, rice, vines, potatoes,tomatoes, top fruit, especially apples, and cucumber. The duration ofprotection is normally dependent on the individual compound selected,and also a variety of external factors, such as climate, whose impact isnormally mitigated by the use of a suitable formulation. The compoundsof the present invention are especially suitable to combat Erysiphegraminis in cereals.

The invention is further illustrated by the following examples.

EXAMPLE 18-t-Butyl-2-(4,6-dimethylpyrimid-2-ylaminomethyl)-1,4-dioxaspiro-(4,5)decane(i) Preparation of 1-(4,6-dimethylpyrimid-2-ylamino)-prop-2-ene

4,6-dimethyl-2-methylsulfonylpyrimidine (93.0 g, 0.5 mol) andarallylamine (250 ml) were heated to reflux for 1 hour. Excessallylamine was distilled off and water (800 ml) was added. Thecrystalline product was filtrated and washed with water. Drying invacuum yields 76.2 g of yellowish crystals (m.p. 62°-63° C.).

(ii) Preparation of 3-(4,6-dimethylpyrimid-2-ylamino)propane-1,2-diol

N-methylmorpholine-N-oxide (64.0 g, 0.47 mol) and osmiumtetroxide (0.7g, 2.75 mmol) were dissolved in a mixture of 180 ml water and 100 mlacetone. 1-(4,6-dimethylpyrimid-2-ylamino)-prop-2-ene (73.5 g, 0.45 mol)in 100 ml acetone was added over a period of 15 minutes. The mixture wasstirred at room temperature for 1 hour and then warmed to 50° C. for 2hours. 10 ml aqueous saturated sodiumhydrogensulphite was then addedtogether with 40 g of diatomaceous earth. After filtration the reactionmixture was evaporated to dryness and the residue extracted withdioxane/ethanol 2:1 (700 ml). Filtration from insoluble material andconcentration of the solution in vacuum caused crystallisation of theproduct. Addition of toluene completed product precipitation, which wasisolated by filtration (83 g, m.p. 124°-127° C.).

(iii) Preparation of8-t-butyl-2-(4,6-dimethylpyrimid-2-ylamino-methyl)-1,4-dioxaspiro(4,5)decane

3-(4,6-dimethylpyrimid-2-ylamino)-propane-1,2-diol (4.0 g, 20 mmol),4-t-butyl cyclohexanone (3.08 g, 20 mmol) and p-toluenesulfonic acid(4.3 g, 22 mmol) in 50 ml benzene were refluxed on a water trap for 1hour. The reaction mixture was washed twice with saturated aqueoussodium carbonate (50 ml), dried with magnesium sulphate and evaporatedin vacuum. Kugelrohr- distillation of the resulting oil yielded 6.0 g ofa colourless oil (b.p. 200° C./0.2 mbar) which was recrystallised fromlight petroleum to yield 5.0 g of colourless crystals (m.p. 121°-124°C.). GLC-MS analysis indicates an approximately 1:1 mixture ofdiastereoisomers (cis/trans).

EXAMPLE 2 8-t-Butyl-2-(4,6-dimethoxypyrimid-2-ylamino-methyl)-1,4-dioxaspiro(4,5)decane (i) Preparation of8-t-butyl-2-(phthalimidomethyl)-1,4-dioxaspiro(4,5)decane

A mixture of 8-t-butyl-2-chloromethyl-1,4-dioxaspiro(4,5)decane (10 g,40 mmol) (prepared as described in EP 281842; see also the referencescited in this document for related compounds), potassium phthalimide(8.9 g, 48 mmol) and a catalytic amount of tetra-n-butyl ammonium iodidein DMF (80 ml) were heated to 120° C. for 3 hours. Additional potassiumphthalimide (2.8 g, 16 mmol) was then added and heating was continuedfor 6 hours. The solvent was then evaporated in vacuo and toluene (150ml) was added. After filtration from insoluble material the organicphase was washed two times with brine (100 ml), dried (MgSO₄) andevaporated in vacuo. The resulting residue (22 g) was purified by flashchromatography on silica (toluene/ethylacetate 3:1) yielding the titlecompound as light yellow crystals (14.5 g, Fp. 97°-115° C.).

(ii) Preparation of 8-t-butyl-2-aminomethyl-1,4-dioxaspiro(4,5)decane

To a warm (50° C.) solution of8-t-butyl-2-(phthalimidomethyl)-1,4-dioxaspiro (4,5)decane (12.5 g, 35mmol) in ethanol (100 ml) was 25 added hydrazine hydrate (3.6 g, 72mmol). The reaction mixture was kept at 50° C. for 1 hour. Lightpetroleum 200 ml was added and insoluble material was filtered off. Thesolvent was evaporated in vacuo. The residue was dissolved in toluene(100 ml) washed with brine (100 ml) and dried (MgSO₄). Evaporation ofthe solvent yielded the title compound as a yellow oil (7.2 g). GCanalysis indicated the compound as existing as a mixture of twodiastereoisomers (cis, cis and cis, trans) in a ratio of 48:52. The NMRspectra are in agreement with the assigned structure.

(iii) Preparation of 8-t-butyl-2-(4,6-dimethoxypyrimid-2-ylaminomethyl)-1,4-dioxaspiro(4,5)decane

8-t-butyl-2-aminomethyl-1,4-dioxaspiro(4,5)decane (3.3 g, 14.5 mmol),4,6-dimethoxy-2-methylsulfonyl-pyrimidine (3.16 g, 14.5 mmol) andpotassium carbonate (2.76 g, 20 mmol) were heated to 160° C. for 1 hour.The reaction mixture was then extracted with toluene and theconcentrated extracts purified by flash chromatography using a 3:1mixture of toluene and ethylacetate. 3.5 g of a faint yellow oil wasobtained which crystallised on standing. NMR analysis indicated theproduct being a mixture of diastereoisomers. M.p.: 76°-106° C.

Elemental analysis: Calc. C: 62.55 H: 8.55 N: 11.50 Found C: 62.75 H:8.42 N: 10.79

EXAMPLES 3 TO 55

By processes similar to those described in Examples 1 and 2 above,further compounds according to the invention were prepared as detailedin Table 1 below. In this table, the compounds are identified byreference to formula I.

                                      TABLE I                                     __________________________________________________________________________     ##STR12##                                     I                              Ex.                                                                           No.                                                                              R.sup.1                                                                          R.sup.2   R.sup.3                                                                            R.sup.4                                                                            X   A       B    l m n                              __________________________________________________________________________     1.                                                                              H                                                                          4-t-C.sub.4 H.sub.9                                                                           CH.sub.3                                                                           CH.sub.3                                                                           O   CH      N    1 1 1                               2.                                                                              H                                                                          4-t-C.sub.4 H.sub.9                                                              OCH.sub.3                                                                        OCH.sub.3 O    CH   N   1       1    1                                   3.                                                                              H                                                                          4-i-C.sub.3 H.sub.7                                                              CH.sub.3                                                                         CH.sub.3  O    CH   N   1       1    1                                   4.                                                                              H                                                                          4-C.sub.6 H.sub.5                                                                CH.sub.3                                                                         CH.sub.3  O    CH   N   1       1    1                                   5.                                                                              H                                                                          3,5-(CH.sub.3).sub.2                                                             CH.sub.3                                                                         CH.sub.3  O    CH   N   1       2    1                                   6.                                                                              H                                                                          4-t-C.sub.5 H.sub.11                                                             CH.sub.3                                                                         CH.sub.3  O    CH   N   1       1    1                                   7.                                                                              H                                                                          2-t-C.sub.4 H.sub.9                                                              CH.sub.3                                                                         CH.sub.3  O    CH   N   1       1    1                                   8.                                                                              H                                                                          2-i-C.sub.3 H.sub.7                                                              CH.sub.3                                                                         CH.sub.3  O    CH   N   1       1    1                                   9.                                                                              H                                                                          2-CH.sub.3                                                                       CH.sub.3                                                                         CH.sub.3  O    CH   N   1       1    1                                  10.                                                                              H            CH.sub.3                                                                           CH.sub.3                                                                           O   CH      N    1 0 1                                 H                                                                          2-C.sub.6 H.sub.5                                                                CH.sub.3                                                                         CH.sub.3  O    CH   N   1       1    1                                     H                                                                          4-CH.sub.3                                                                       CH.sub.3                                                                         CH.sub.3  O    CH   N   1       1    1                                     H                                                                          2-CH.sub.3 -5-i-C.sub.3 H.sub.7                                                  CH.sub.3                                                                         CH.sub.3  O    CH   N   1       2    1                                     H                                                                          5-CH.sub.3 -2-i-C.sub.3 H.sub.7                                                  CH.sub.3                                                                         CH.sub.3  O    CH   N   1       2    1                                     H  (adamantyl)                                                                             CH.sub.3                                                                           CH.sub.3                                                                           O   CH      N    1 3 1                                 H                                                                          3-i-C.sub.3 H.sub.7                                                              CH.sub.3                                                                         CH.sub.3  O    CH   N   1       1    1                                     H                                                                          2-C.sub.6 H.sub.11                                                               CH.sub.3                                                                         CH.sub.3  O    CH   N   1       1    1                                     H                                                                          2,4-(CH.sub.3).sub.2                                                             CH.sub.3                                                                         CH.sub.3  O    CH   N   1       2    1                                     H                                                                          2,6-(CH.sub.3).sub.2                                                             CH.sub.3                                                                         CH.sub.3  O    CH   N   1       2    1                                  20.                                                                              H            CH.sub.3                                                                           CH.sub.3                                                                           O   CH      N    1 0 3                                 H            CH.sub.3                                                                           CH.sub.3                                                                           O   CH      N    1 0 2                                 H            CH.sub.3                                                                           CH.sub.3                                                                           O   CH      N    1 0 7                                 H                                                                          3,3,5-(CH.sub.3).sub.3                                                           CH.sub.3                                                                         CH.sub.3  O    CH   N   1       3    1                                     H                                                                          4-t-C.sub.4 H.sub.9                                                              Cl OCH.sub.3 O    CH   N   1       1    1                                     H                                                                          4-t-C.sub.4 H.sub.9                                                              OCH.sub.3                                                                        OCH.sub.3 O    N    N   1       1    1                                     H                                                                          4-t-C.sub.4 H.sub.9                                                              H  H         O    CCF.sub.3                                                                          CH  1       1    1                                     H            CH.sub.3                                                                           CH.sub.3                                                                           O   CH      N    1 0 5                                 H                                                                          3,3,5,5-(CH.sub.3).sub.4                                                         CH.sub.3                                                                         CH.sub.3  O    CH   N   1       4    1                                     H                                                                          3,4-(CH.sub.2).sub.4                                                             CH.sub.3                                                                         CH.sub.3  O    CH   N   1       2    1                                  30.                                                                              H                                                                          4-t-C.sub.4 H.sub.9                                                              CH.sub.3                                                                         CH.sub.3  a-CH.sub.2                                                                         CH   N   1       1    1                                     H                                                                          4-t-C.sub.4 H.sub.9                                                              CH.sub.3                                                                         CH.sub.3  e-CH.sub.2                                                                         CH    N  1       1    1                                     H                                                                          4-t-C.sub.5 H.sub.11                                                             CH.sub.3                                                                         OCH.sub.3 O    CH   N   1       1    1                                     H                                                                          4-i-C.sub.3 H.sub.7                                                              OCH.sub.3                                                                        OCH.sub.3 O    CH   N   1       1    1                                     H                                                                          4-CH.sub.3                                                                       OCH.sub.3                                                                        OCH.sub.3 O    CH   N   1       1    1                                     H                                                                          4-C.sub.6 H.sub.5                                                                OCH.sub.3                                                                        OCH.sub.3 O    CH   N   1       1    1                                     H                                                                          4,4-(CH.sub.2).sub.5                                                             OCH.sub.3                                                                        OCH.sub.3 O    CH   N   1       2    1                                     H                                                                          4,4-(CH.sub.2).sub.5                                                             CH.sub.3                                                                         CH.sub.3  O    CH   N   1       2    1                                     H                                                                          4-t-C.sub.4 H.sub.9                                                              OH CH.sub.3  O    C(n-C.sub.4 H.sub.9)                                                               N   1       1    1                                     H                                                                          4-t-C.sub.5 H.sub.11                                                             OH CH.sub.3  O    C(n-C.sub.4 H.sub.9)                                                               N   1       1    1                                  40.                                                                              H                                                                          4-t-C.sub.5 H.sub.11                                                          n-C.sub.5 H.sub.11                                                               CH.sub.3                                                                         O          CH  N    1   1       1                                          H                                                                          4-t-C.sub.4 H.sub.9                                                           n-C.sub.5 H.sub.11                                                               CH.sub.3                                                                         O         CH   N    1   1       1                                          H                                                                          4-t-C.sub.4 H.sub.9                                                           s-C.sub.4 H.sub.9                                                                CH.sub.3                                                                         O         CH   N    1   1       1                                          H                                                                          4-t-C.sub.5 H.sub.11                                                          s-C.sub.4 H.sub.9                                                                CH.sub.3                                                                         O         CH   N    1   1       1                                          H                                                                          4-t-C.sub.4 H.sub.9                                                           t-C.sub.4 H.sub.9                                                             t-C.sub.4 H.sub.9                                                                O  CH        N    1    1   1                                                  H                                                                          4-t-C.sub.5 H.sub.11                                                          t-C.sub.4 H.sub.9                                                             t-C.sub.4 H.sub.9                                                                O  CH        N    1    1   1                                                  H                                                                          4-t-C.sub.4 H.sub.9                                                              CF.sub.3                                                                         C.sub.6 H.sub.5                                                                         O    CH   N   1       1    1                                     H                                                                          4-t-C.sub.5 H.sub.11                                                             CF.sub.3                                                                         C.sub.6 H.sub.5                                                                         O    CH   N   1       1    1                                     H                                                                          4-t-C.sub.4 H.sub.9                                                              CH.sub.3                                                                         C.sub.6 H.sub.5                                                                         O    CH   N   1       1    1                                     H                                                                          4-t-C.sub. 5 H.sub.11                                                            CH.sub.3                                                                         C.sub.6 H.sub.5                                                                         O    CH   N   1       1    1                                  50.                                                                              H                                                                          4-t-C.sub.4 H.sub.9                                                              H  H         O    CH   N   1       1    1                                     H                                                                          4-t-C.sub.5 H.sub.11                                                             H  H         O    CH   N   1       1    1                                     H                                                                          4-t-C.sub.5 H.sub.11                                                             H  CH.sub.3  O    CH   N   1       1    1                                     H                                                                          4-t-C.sub.4 H.sub.9                                                              H  CH.sub.3  O    CH   N   1       1    1                                     CH.sub.3                                                                   4-t-C.sub.4 H.sub.9                                                              CH.sub.3                                                                         CH.sub.3  O    CH   N   1       1    1                                     CH.sub.3                                                                   4-t-C.sub.5 H.sub.11                                                             CH.sub.3                                                                         CH.sub.3  O    CH   N   1       1    1                                  __________________________________________________________________________

Physical data for the above compounds are set out in Table II, III andIV below.

                  TABLE II                                                        ______________________________________                                        Analysis (%)                                                                  Ex.   C                H            N                                         No.   Calc.  Found     Calc. Found  Calc.                                                                              Found                                ______________________________________                                         2    62.44  62.75     8.55  8.42   11.50                                                                              10.79                                15    69.20  70.14     8.26  8.29   12.75                                                                              12.32                                16    70.30  69.56     9.50  9.44   13.66                                                                              11.79                                17    70.15  70.17     9.25  9.31   11.68                                                                              11.72                                18    66.80  67.27     8.91  8.96   13.75                                                                              13.49                                20    66.80  67.19     8.91  9.25   13.75                                                                              13.06                                21    65.94  66.35     8.64  8.69   14.42                                                                              14.21                                22    69.76  70.25     9.75  10.05  11.62                                                                              11.39                                23    67.67  67.69     9.15  9.62   13.15                                                                              13.09                                29    68.84  68.85     8.81  9.48   12.67                                                                              12.12                                32    63.29  62.77     8.78  8.54   11.07                                                                              10.17                                33    60.52  60.91     8.32  8.11   11.95                                                                              10.87                                38    67.48  67.23     9.53  9.79   10.73                                                                              11.01                                39    68.11  67.82     9.69  10.04  10.36                                                                              10.41                                40    71.42  71.20     10.24 10.33  10.41                                                                              10.55                                41    70.91  70.97     10.09 10.62  10.79                                                                              10.84                                42    70.36  70.82     9.92  9.96   11.19                                                                              10.84                                43    70.91  70.97     10.09 9.79   10.79                                                                              10.71                                44    71.90  71.86     10.38 10.79  10.06                                                                               9.72                                45    72.34  72.71     10.51 9.96    9.73                                                                               9.41                                46    64.13  62.19     6.73  6.97    9.35                                                                               8.18                                48    72.88  71.73     8.41  8.71   10.62                                                                              10.74                                49    73.41  73.07     8.61  9.07   10.26                                                                              10.27                                54    69.12  68.41     9.57  9.86   12.09                                                                              12.45                                55    69.76  68.49     9.75  10.09  11.62                                                                              11.50                                ______________________________________                                    

                  TABLE III                                                       ______________________________________                                        Melting point (°C.)                                                    Ex. No.                Ex. No.                                                ______________________________________                                         1        89-112       32        90-112                                        3       66-73         33        85-110                                        4        99-108       34       110-118                                       14       43-52         35        95-115                                       15       93-96         36       105-107                                       22       80-85         37       95-97                                         24        83-101       47       105-115                                       25       119-128       48       100-105                                       26       64-80         49       120-131                                       28       60-65                                                                ______________________________________                                    

                  TABLE IV                                                        ______________________________________                                        Molecular weight                                                              (determined by mass spectrometry)                                             Ex. No.         Calc.  Found                                                  ______________________________________                                         3              319    319                                                     4              353    353                                                     5              305    305                                                     6              347    347                                                     7              333    333                                                     8              307    307                                                     9              291    291                                                    10              277    277                                                    11              353    353                                                    12              291    291                                                    13              321    321                                                    14              321    321                                                    16              307    307                                                    18              305    305                                                    19              305    305                                                    20              305    305                                                    21              291    291                                                    22              361    361                                                    23              319    319                                                    24              369    369                                                    25              366    366                                                    26              372    372                                                    27              333    333                                                    30              331    331                                                    31              331    331                                                    40              403    403                                                    41              389    389                                                    42              375    375                                                    43              389    389                                                    46              449    449                                                    47              463    463                                                    48              395    395                                                    49              409    409                                                    50              305    305                                                    51              319    319                                                    52              333    333                                                    53              319    319                                                    54              347    347                                                    55              361    361                                                    ______________________________________                                    

Fungicidal activity

The fungicidal activity of compounds of the invention was investigatedby means of the following tests.

(a) Antisporulant activity against vine downy mildew (Plasmoparaviticola; PVA)

The test is a direct antisporulant one using a foliar spray. The lowersurfaces of leaves of whole vine plants (cv Gabernet Sauvignon),approximately 8 cm high, are inoculated by spraying with an aqueoussuspension containing 5×10⁴ sporangia/mi. The inoculated plants are keptfor 24 hours at 21° C. in a high humidity compartment, then 24 hours atglasshouse ambient temperature and humidity. Infected leaves are sprayedon their lower surfaces with a solution of active material in 1:1water/acetone containing 0.04% "TWEEN 20" (Trade Mark; a polyoxyethylenesorbitan ester surfactant). Plants are treated using an automatedsprayline with an atomising nozzle. The concentration of the compound is600 ppm, and the spray volume is 750 l/ha. After spraying, the plantsare returned to normal glasshouse conditions for 96 hours and are thentransferred to the high humidity compartment for 24 hours to inducesporulation. Assessment is based on the percentage of the leaf areacovered by sporulation compared with that on control leaves.

(b) Direct protectant activity against broad bean grey mould (Botrytiscinerea; BCB)

The test is a direct protectant foliar spray. The upper surfaces ofleaves of broad bean plants with two leaf pairs (cv The Sutton) aresprayed with the test compound at a dosage of 600 ppm using an automatedsprayline as described under (a). 24 hours after spraying the leaves areinoculated with an aqueous suspension containing 10⁶ conidia/ml. For 4days after inoculation plants are kept in a high humidity compartment at22° C. Disease is assessed 4 days after inoculation, based on thepercentage of leaf surface area covered by lesions.

(c) Activity against wheat leafspot (Leptosphaeria nodorum; LN.)

The test is a direct therapeutic foliar spray. Leaves of wheat plants(cv Norman), at the single leaf stage, are inoculated by spraying withan aqueous suspension containing 1.5×10⁶ conidia/ml. The inoculatedplants are kept for 24 hours in a high humidity compartment prior totreatment. The plants are sprayed with a solution of the test compoundat a dosage of 600 ppm using an automated sprayline as described under(a). After drying, the plants are kept for 6-8 days at 22° C. andmoderate humidity (70%). Assessment is based on the density of lesionsper leaf compared with that on leaves of control plants.

(d) Activity against barley powdery mildew (Erysiphe graminis f.sp.hordei; EG)

The test is a direct therapeutic foliar spray. Leaves of barleyseedlings, (cv. Golden Promise) at the single leaf stage are inoculatedby dusting with mildew conidia one day prior to treatment with the testcompound. The inoculated plants are kept overnight at glasshouse ambienttemperature (18° C.) and humidity (40%) prior to treatment. The plantsare sprayed with the test compound at a dosage of 600 ppm using anautomated sprayline as described under (a). After drying, plants arereturned to a compartment at 18° C. and 40% humidity for up to 7 days.Assessment is based on the percentage of leaf area covered bysporulation compared with that on leaves of control plants.

(e) Activity against rice leaf blast (Pyricularia oryzae; PO)

The test is a direct therapeutic foliar spray. The leaves of riceseedlings (cv Aichiaishi--about 30 seedlings per pot) at the stage ofthe second leaf beginning to bend are sprayed with an aqueous suspensioncontaining 10⁵ spores/ml 24 hours prior to treatment with the testcompound. The inoculated plants are kept overnight in high humidity andthen allowed to dry before spraying with the test compound at a dosageof 600 ppm using an automated sprayline as described under (a). Aftertreatment the plants are kept in a rice compartment at 25°-30° C. andhigh humidity. Assessments are made 4-5 days after treatment and arebased on the density of necrotic lesions per leaf when compared withcontrol plants.

(f) Activity against tomato early blight (Alternaria solani; AS)

This test measures the contact prophylactic activity of test compoundsapplied as a foliar spray. Tomato seedlings (cv Outdoor Girl) are grownto the stage at which the second true leaf is expanded. The plants aretreated using an automated sprayline as described under (a). Testcompounds are applied as solutions or suspensions in a mixture ofacetone and water (50:50 v/v) containing 0.04% surfactant ("TWEEN20"--Trade Mark). One day after treatment the seedlings are inoculatedby spraying the leaf upper surfaces with a suspension of A. solaniconidia containing 10⁴ spores/mi. For 4 days after inoculation plantsare kept moist in a humidity compartment at 21° C. Disease is assessed 4days after inoculation, based on the percentage of leaf surface areacovered by lesions.

(g) Activity against wheat eyespot in-vitro (Pseudocercosporellaherpotrichoides; PH)

This test measures the in vitro activity of compounds against the funguscausing wheat eyespot. The test compound is dissolved or suspended inacetone and is added into 4 ml aliquots of half strength Potato DextroseBroth (PDB) dispended in 25-compartment petri dishes to give a finalconcentration of 10 ppm compound and 3.5% acetone. The fungal inoculumconsists of mycelial fragments of P. herpotrichoides grown in halfstrength PDB in shaken flasks and added to the broth to provide 5×10⁴fragments/ml broth. Petri dishes are incubated at 20° C. for 10 daysuntil the assessment of mycelial growth.

(h) Activity against apple scab in-vitro (Venturia inaequalis: VI)

This test measures the in-vitro activity of compounds against V.inaequalis that causes apple scab. The test compound in acetone is addedinto 4 ml aliquots of half strength Potato Dextrose Broth dispensed in25-compartment petri dishes to give final concentrations of 10 ppm. Thefungal inoculum consists of mycelial fragments and spores of V.inaequalis grown on malt agar and added to the broth to provide 5×10⁴propagules/ml broth. Petri dishes are incubated at 20° C. for 10 daysuntil the assessment of myceltal growth.

The extent of disease control in all the above tests is expressed as arating compared with either an untreated control or adiluent-sprayed-control, according to the criteria:

0=less than 50% disease control

1=about 50-80% disease control

2=greater than 80% disease control

The results of the tests are set out in Table V below.

                  TABLE V                                                         ______________________________________                                        Comp. PIP     BCB    LN    EG   PO    AS   PH   VI                            ______________________________________                                         1    0       0      0     2    0     1    0    0                              2    0       0      0     2    0     1    0    1                              3    0       0      0     2    0     0    0    1                              4    0       0      0     2    0     0    0    1                              5    0       0      0     2    0     0    0    1                              6    0       2      0     2    0     1    0    2                              7    0       0      0     0    0     1    0    0                              8    0       0      0     0    0     0    0    1                              9    0       0      0     0    0     0    0    1                             10    0       0      0     0    0     1    0    1                             11    0       0      0     0    0     0    0    1                             12    0       0      0     1    0     0    0    1                             13    0       0      0     1    0     0    0    1                             14    0       0      0     0    0     0    0    1                             15    0       0      0     0    0     0    0    1                             16    1       0      0     2    0     0    1    1                             17    0       0      0     0    0     0    0    1                             18    0       0      0     1    0     0    0    1                             19    2       0      0     0    0     0    0    0                             20    0       2      0     0    0     0    2    2                             21    0       0      0     0    0     0    1    1                             22    0       0      0     0    0     0    0    1                             23    0       0      0     0    0     0    0    1                             24    0       2      0     2    0     0    2    1                             25    0       1      0     2    0     0    0    0                             26    2       0      0     2    0     1    1    1                             27    0       0      0     0    0     0    0    1                             28    0       0      1     0    0     0    0    0                             29    0       0      0     0    2     0    0    1                             30    0       0      0     2    0     2    0    1                             31    0       0      0     2    0     0    0    1                             32    0       1      0     2    0     2    0    0                             33    0       0      0     2    0     0    0    0                             34    0       0      0     0    0     0    0    0                             35    0       1      0     0    0     0    0    0                             36    0       0      0     0    0     0    0    0                             37    0       0      0     1    0     0    1    1                             38    0       0      0     0    0     2    0    1                             39    0       0      0     0    0     2    0    1                             40    0       0      0     2    0     2    0    0                             41    0       0      0     2    0     0    0    2                             42    0       0      0     2    0     2    0    1                             43    0       0      0     2    0     2    0    1                             44    0       2      0     0    0     0    0    0                             45    0       0      0     0    0     0    0    0                             46    0       0      0     1    0     0    0    0                             47    0       0      0     1    0     1    0    0                             48    0       0      0     2    0     1    0    0                             49    0       0      0     2    0     1    0    0                             50    0       0      0     2    0     1    0    2                             51    0       0      0     2    0     1    0    2                             52    0       0      0     2    0     2    0    2                             53    0       0      0     2    0     1    0    2                             54    0       0      0     2    0     0    0    0                             55    0       0      0     2    0     0    0    0                             ______________________________________                                    

I claim:
 1. A method of combating fungi at a locus which comprisestreating the locus with a fungicidally effective amount of a compound ofthe formula I: ##STR13## or an acid-addition salt thereof in whichXrepresents O or CH₂, R¹ represnts a hydrogen atom or an optionallysubstituted alkyl, cycloalkyl, haloalkyl, alkenyl, alkynyl, aryl oraralkyl group, R² represents an optionally substituted alkyl,cycloalkyl, cycloalkylalkyl, alkoxy, alkyoxyalkyl, aryl or aryloxygroup, or R², together with the ring to which it is attached, representsa polycyclic hydrocarbyl group, A represents a group CR⁵ and Brepresents a nitrogen atom, R³, R⁴ and R⁵ each independently represent ahydrogen or halogen atom, a hydroxy or cyano group or an optionallysubstituted alkyl, alkenyl, alkynyl, haloalkyl, alkoxyalkyl, aralkyl,aryl, alkylamino, alkylthio or alkoxy group, l represents an integerfrom 1 to 3, m represents an integer from 1 to 6, and n represents zeroor an integer from 1 to
 3. 2. A method according to claim 1, in whichany alkyl, alkenyl, alkynyl part of any of the substituents R¹ to R⁵contains up to 10 carbon atoms, any cycloalkyl part of any of thesubstituents R¹ to R⁵ contains from 3 to 8 carbon atoms, any alkylenechain contains from 1 to 8 chain members, and any aryl part of any ofthe substituents R¹ to R⁵ contains 6 to 10 carbon atoms, and in whicheach optionally substituted group independently is substituted by one ormore halogen atoms or nitro, cyano, C₁₋₆ alkyl, C₃₋₆ cycloalkyl, C₁₋₆haloalkyl, C₃₋₆ halocycloalkyl, C₁₋₆ alkoxy, C₁₋₆ haloalkoxy, optionallysubstituted amino, formyl, C₁₋₆ alkoxycarbonyl, carboxyl, phenyl orhalo- or dihalo-phenyl groups.
 3. A method according to claim 1, inwhich X represents O.
 4. A method according to claim 1, in which R¹represents a hydrogen atom, a C₁₋₆ alkyl, C₃₋₆ cycloalkyl, C₂₋₆ alkenyl,C₂₋₆ alkynyl, phenyl or benzyl group, each group optionally substitutedby one or more halogen atoms, or C₁₋₄ alkyl, C₁₋₄ haloalkyl, C₁₋₄alkoxy, C₁₋₄ alkylamino, C₁₋₄ dialkylamino or phenylamino groups.
 5. Amethod according to claim 4, in which R¹ represents a hydrogen atom or amethyl or ethyl group optionally substituted by up to three chlorine orfluorine atoms, an ethenyl, propenyl or propynyl group of a phenyl orbenzyl group.
 6. A method according to claim 1, in which R² or each R²independently represents a C₁₋₁₀ alkyl, C₃₋₆ cycloalkyl, C₃₋₈cycloalkyl-C₁₋₆ alkyl, C₁₋₆ alkoxy, C₁₋₁₀ alkoxy-C₁₋₆ alkyl or phenylgroup, R² or each R² together with the ring to which they are attached,represents a C₇₋₂₀ polycyclic group, each of the above groups optionallysubstituted by one or more halogen atoms, or C₁₋₄ alkyl, C₁₋₄ haloalkylor C₁₋₄ alkoxy groups.
 7. A method according to claim 6, in which R²represents a C₃₋₈ alkyl group.
 8. A method according to claim 1, inwhich R² represents a secondary butyl, tertiary butyl or tertiary amylgroup attached to the 4-position of the cycloalkyl ring.
 9. A methodaccording to claim 1, in which m represents 1 or
 2. 10. A methodaccording to claim 1, in which R² is attached to the positions 3, 4 or 5of the cycloalkyl ring.
 11. A method according to claim 1, in which R³,R⁴, and R⁵ each independently represent a hydrogen or halogen atom, oran optionally substituted C₁₋₆ alkyl, C₁₋₆ alkenyl, C₁₋₆ haloalkyl,benzyl, phenyl or C₁₋₆ alkoxy group, each group optionally substitutedby one or more halogen atoms or a C₁₋₄ alkyl, C₁₋₄ haloalkyl, C₁₋₄alkoxy, C₁₋₄ alkylamino, C₁₋₄ dialkylamino or phenylamino groups.
 12. Amethod according to claim 11, in which R³ and R⁴ each independentlyrepresent a hydrogen or halogen atom, a hydroxy group or a methyl,ethyl, propyl, butyl, pentyl, hexyl, phenyl, methoxy or ethoxy group,each group optionally substituted by up to three chlorine or fluorineatoms.
 13. A method according to claim 11 in which R⁵ represents ahydrogen or halogen atom, or a methyl, ethyl, propyl, methoxy or ethoxygroup, each group optionally substituted by up to three chlorine orfluorine atoms.
 14. A method according to claim 1, in which l and nrepresent
 1. 15. A method according to claim 1, wherein said locuscomprises plants subject to or subjected to fungal attack, seeds of suchplants or the medium in which the plants are to be grown.
 16. A methodaccording to claim 15, wherein said locus comprises cereals.